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Date: Sat, 31 Mar 2012 09:37:52 +0300
From: Shmulik Ladkani <shmulik.ladkani@gmail.com>
To: Mike Dunn <mikedunn@newsguy.com>
Subject: Re: [PATCH 4/4] MTD: drivers return max_bitflips, mtd returns -EUCLEAN
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Cc: Brian Norris <computersforpeace@gmail.com>, linux-mtd@lists.infradead.org,
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Hi Mike,

On Fri, 30 Mar 2012 18:05:55 -0700 Mike Dunn <mikedunn@newsguy.com> wrote:
> > This seems wrong in the case that mtd->euclean_threshold == 0. 
> 
> > This could be the case for any of the following:
> > (1) NAND that uses ECC_NONE
> > (2) NAND drivers with HW_ECC that don't initialize chip->ecc.strength
> > (3) MTD without ECC (e.g., NOR)
> > (4) Other drivers that might have missed initializing mtd->ecc_strength
> > 
> 
> 
> > If I'm correct, (3) is quite significant, since non-ECC'd MTDs would
> > produce EUCLEAN statuses on every read.
> 
> 
> Yup.  Again, oops!
> 

Please re-consider having the 'euclean_threshold' comparison within the
NAND infrastructure (nand_base.c and clones), instead of within the
generic 'mtd_read()' wrapper, as discussed in [1].

This would inherently fix (3).

For code unification, we can have a small inlined function that does the
comparison, which may be used by nand_base.c and the clones.

[1]
http://lists.infradead.org/pipermail/linux-mtd/2012-March/040371.html
http://lists.infradead.org/pipermail/linux-mtd/2012-March/040343.html

Regards,
Shmulik